Physical binding energies using the electron localization function in 4-hydroxyphenylboronic acid co-crystals with aza donors

Binding energies are traditionally simulated using cluster models by computation of each synthon for each individual co-crystal former. However, our investigation of the binding strengths using the electron localization function (ELF) reveals that these can be determined directly from the crystal supercell computations. We propose a new modeling protocol for the computation of physical binding energies directly from bulk simulations using ELF analysis. In this work, we establish a correlation between ELF values and binding energies calculated for co-crystals of 4-hydroxyphenylboronic acid (4HPBA) with four different aza donors using density functional theory with varying descriptions of dispersion. Boronic acids are gaining significant interest in the field of crystal engineering, but theoretical studies on their use in materials are still very limited. Here, we present a systematic investigation of the non-covalent interactions in experimentally realized co-crystals. Prior diffraction studies on these complexes have shown the competitive nature between the boronic acid functional group and the para-substituted phenolic group forming heteromeric interactions with aza donors. We determine the stability of the co-crystals by simulating their lattice energies, and the different dispersion descriptions show similar trends in lattice energies and lattice parameters. Our study bolsters the experimental observation of the boronic acid group as a competitive co-crystal former in addition to the well-studied phenolic group. Further research on correlating ELF values for physical binding could potentially transform this approach to a viable alternative for the computation of binding energies.

Bulky countercation effects on the crystal packing of anionic dithiooxalato-containing Ni(ii), Pd(ii) and Pt(ii) complexes: spectroscopic–redox correlations

The metal ion, countercation and crystallization solvent control the packing of bis(dithiooxalato-k2S,S′)metallate(ii) complex anions in the solid state.

3-Pyridinylboronic acid normalizes the effects of 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine exposure in zebrafish embryos

1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is a neurotoxin that damages dopaminergic neurons. Zebrafish has been shown to be a suitable model organism to investigate the molecular pathways in the pathogenesis of Parkinson's disease and also for potential therapeutic agent research. Boron has been shown to play an important role in the neural activity of the brain. Boronic acids are used in combinatorial approaches in drug design and discovery. The effect of 3-pyridinylboronic acid which is an important sub-class of heterocyclic boronic acids has not been evaluated in case of MPTP exposure in zebrafish embryos. Accordingly, this study was designed to investigate the effects of 3-pyridinylboronic acid on MPTP exposed zebrafish embryos focusing on the molecular pathways related to neurodegeneration and apoptosis by RT-PCR. Zebrafish embryos were exposed to MPTP (800 μM); MPTP + Low Dose 3-Pyridinylboronic acid (50 μM) (MPTP + LB) and MPTP + High Dose 3-Pyridinylboronic acid (100 μM) (MPTP + HB) in well plates for 72 hours post fertilization. Results of our study showed that MPTP induced a P53 dependent and Bax mediated apoptosis in zebrafish embryos and 3-pyridinylboronic acid restored the locomotor activity and gene expressions related to mitochondrial dysfunction and oxidative stress due to the deleterious effects of MPTP, in a dose-dependent manner.

Supramolecular zwitterions based on a novel boronic acid–squarate dianion synthon

We report a novel heterodimeric charge-assisted hydrogen bonding synthon and prove its robustness by preparation of a three-component co-crystal.

Supramolecular networks in molecular complexes of pyridine boronic acids and polycarboxylic acids: synthesis, structural characterization and fluorescence properties

3- and 4-pyridineboronic acids have been combined with trimesic and pyromellitic acids to give three molecular complexes.

Bis[3-(dihydroxy-boryl)anilinium] sulfate

In the title compound, 2C₆H₉BNO₂⁺·SO₄²⁻, the dihydroxy­boryl group of one of the two independent boronic acid mol­ecules participates in (B)O—H⋯O_B and N—H⋯O_B hydrogen bonds, while the second is involved mainly in the formation of the charge-assisted heterodimeric synthon –B(OH)₂⋯⁻O₂SO₂⁻. These aggregates are further connected through N—H⋯O_sulfate inter­actions, forming a complex three-dimensional hydrogen-bonded network.

Benzene-1,4-diboronic acid-4,4'-bipyridine-water (1/2/2)

In the presence of water, benzene-1,4-diboronic acid (1,4-bdba) and 4,4'-bipyridine (4,4'-bpy) form a cocrystal of composition (1,4-bdba)(4,4'-bpy)(2)(H(2)O)(2), in which the molecular components are organized in two, so far unknown, cyclophane-type hydrogen-bonding patterns. The asymmetric unit of the title compound, C(6)H(8)B(2)O(4).2C(10)H(8)N(2).2H(2)O, contains two 4,4'-bpy, two water molecules and two halves of 1,4-bdba molecules arranged around crystallographic inversion centers. The occurrence of O-H...O and O-H...N hydrogen bonds involving the water molecules and all O atoms of boronic acid gives rise to a two-dimensional hydrogen-bonded layer structure that develops parallel to the (01-4) plane. This supramolecular organization is reinforced by pi-pi interactions between symmetry-related 4,4'-bpy molecules.